diff options
Diffstat (limited to 'doc/crypto/PKCS7_sign.pod')
-rw-r--r-- | doc/crypto/PKCS7_sign.pod | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/doc/crypto/PKCS7_sign.pod b/doc/crypto/PKCS7_sign.pod index fc7e649b34..ffd0c734b0 100644 --- a/doc/crypto/PKCS7_sign.pod +++ b/doc/crypto/PKCS7_sign.pod @@ -51,6 +51,24 @@ If present the SMIMECapabilities attribute indicates support for the following algorithms: triple DES, 128 bit RC2, 64 bit RC2, DES and 40 bit RC2. If any of these algorithms is disabled then it will not be included. +If the flags B<PKCS7_PARTSIGN> is set then the returned B<PKCS7> structure +is just initialized ready to perform the signing operation. The signing +is however B<not> performed and the data to be signed is not read from +the B<data> parameter. Signing is deferred until after the data has been +written. In this way data can be signed in a single pass. Currently the +flag B<PKCS7_DETACHED> B<must> also be set. + +=head1 NOTES + +Currently the flag B<PKCS7_PARTSIGN> is only supported for detached +data. If this flag is set the returned B<PKCS7> structure is B<not> +complete and outputting its contents via a function that does not +properly finalize the B<PKCS7> structure will give unpredictable +results. + +At present only the SMIME_write_PKCS7() function properly finalizes the +structure. + =head1 BUGS PKCS7_sign() is somewhat limited. It does not support multiple signers, some @@ -64,10 +82,6 @@ signed due to memory restraints. There should be a way to sign data without having to hold it all in memory, this would however require fairly major revisions of the OpenSSL ASN1 code. -Clear text signing does not store the content in memory but the way PKCS7_sign() -operates means that two passes of the data must typically be made: one to compute -the signatures and a second to output the data along with the signature. There -should be a way to process the data with only a single pass. =head1 RETURN VALUES @@ -82,4 +96,6 @@ L<ERR_get_error(3)|ERR_get_error(3)>, L<PKCS7_verify(3)|PKCS7_verify(3)> PKCS7_sign() was added to OpenSSL 0.9.5 +The B<PKCS7_PARTSIGN> flag was added in OpenSSL 0.9.8 + =cut |